This application claims priority under 35 USC 119(a) to patent application No. 2003-75948 filed in Japan on 21 Jan. 2003, the content of which is incorporated herein by reference in its entirety.
The present invention pertains to a workpiece transport apparatus transporting glass substrate, semiconductor wafer, and/or other such workpiece during manufacture of semiconductor, liquid crystal display element, EL (electroluminescent), PDP (plasma display panel) and/or other such flat panel display, solar cell panel, and/or the like; and is in particular related to a strategy for smoothly flipping a workpiece so as to reverse front and back sides thereof for the purpose of carrying out processing of the backside, and/or of both sides, of the workpiece.
During cleaning, photolithography, and/or other such operations carried out on glass substrates and/or semiconductor wafers (hereinafter collectively referred to as “workpiece(s)”) at sites at which semiconductors, flat panel displays, solar cells, and/or the like are manufactured, where a need has arisen to flip so as to reverse front and back sides of a workpiece, mechanical chucks, vacuum chucks, electrostatic chucks, and other such chuck mechanisms have conventionally been employed to flip the workpiece while supporting the end of the workpiece or holding the backside of the workpiece against another surface.
As shown in FIGS. 20 and 21, in one example of such a workpiece transport apparatus, transport workpiece 201 is transported through four transport locations P1 through P4 (transport location P1 being a location occupied following application of liquid coating, P2 being a workpiece side cleaning processing location, P3 being a standby location, and P4 being a location occupied following the operation), workpiece 201 being flipped as it is transported so as to reverse front and back sides thereof during transport from transport location P1 to P2 (see, e.g., Japanese Patent Application Publication Kokai No. H10-264071 (1998)). Moreover, flipping of workpiece 201 so as to reverse front and back sides thereof is carried out by using a motor (not shown) constituting drive unit 204 for plurality of mechanical chuck means 202, . . . as drive source to rotarily drive workpiece 201 in the direction indicated by arrow 205 while the periphery thereof is chucked at prescribed locations by chuck appendages 203 of mechanical chuck means 202. Chucking of workpiece 201 by chuck appendages of such respective chuck means 202 is carried out by way of sliding shaft 207 which engages in sliding action as a result of being directly driven by an air cylinder. Where this is the case, transfer of the workpiece among respective transport locations P1 through P4 may be carried out by means of a separate robot, not shown.
However, with the foregoing conventional workpiece transport apparatus, because workpiece 201 is chucked by chuck appendages 203 of plurality of mechanical chuck means 202, . . . , increase in the size of the workpiece will cause occurrence of bowing at the workpiece, reducing chuck reliability. This increases the likelihood of occurrence of workpiece droppage, breakage, cracking, chipping and/or other such problems during transport and flipping to reverse front and back sides thereof. And where the workpiece was already bowed at the outset, chucking is made all the more difficult.
Furthermore, because chucking is carried out by way of sliding shaft 207, there is a concern that particles will be generated by the sliding shaft and/or components coming into sliding contact therewith as well as components carrying out rotary driving. And because there are many mechanical parts and apparatus constitution is complex, not only is failure likely to occur and much labor expended during servicing thereof, but the apparatus also tends to be large in size.
In addition, where a vacuum chuck or electrostatic chuck is employed instead of a mechanical chuck, a possibility exists that generation of static electricity will affect the workpiece and/or the process.
The present invention was conceived in light of such issues, it being an object thereof to provide a workpiece transport apparatus capable of definitively flipping workpiece(s) without occurrence of workpiece droppage, breakage, cracking, chipping and/or the like during transport and/or flipping to reverse front and back sides thereof, capable of reducing the number of mechanical parts to a minimum, simplifying servicing procedures, and increasing the compactness of the apparatus; and capable of definitively preventing workpiece(s) and/or process(es) from being adversely affected by static electricity.